The invention relates to a method known as “Integrated Reservoir Optimization” (IRO) which includes a method for monitoring and controlling the extraction of fluid and gas deposits from subsurface geological formations. This includes a method for monitoring the status of fluid and gas deposits in subsurface geological formations and controlling the location and use of physical resources and extraction rates to maximize the extraction of such deposits from the subsurface geological formations.
During the production life cycle of oil and gas extracted from reservoir fields in geological formations, certain stages are followed which include exploration, appraisal, reservoir development, production decline, and abandonment of the reservoir. Important decisions must be made at each of these stages in order to properly allocate resources and to assure that the reservoir meets its production potential. In the early stages of the production life cycle, one begins with almost complete ignorance about the distribution of internal properties within the reservoir. As development continues, diverse types of reservoir data are collected, such as seismic, well logs, and production data. That reservoir data are combined to construct an evolving understanding of the distribution of reservoir properties in an earth formation. Therefore, the understanding of that reservoir data is key to making proper reservoir management decisions.
Various prior art approaches that the oil and gas industry has taken to reservoir management have been reported in numerous books and technical journal articles, such as are listed in the References section toward the end of this specification. For example, in the reservoir management method taught in the Satter and Thakur book cited in the References section below, short and long-term goals for managing a gas or oil reservoir are first identified. A plurality of data, which is subsequently collected about the reservoir, are then used to develop a reservoir management plan, also called a development plan. The development plan is then implemented by drilling wells, setting production and injection rates for the reservoir, and performing workover operations. As oil and/or gas is extracted from the reservoir, new data are obtained and the goals and development plans for managing the reservoir are periodically re-evaluated to maximize production of gas and/or oil from the reservoir. As the reservoir is depleted, the goals and development plans are changed, and eventually the reservoir is abandoned.
Some U.S. patents teach and claim various steps in the processes of locating and developing reservoirs, such as, but not limited to, collection of reservoir data, such as seismic, well logs and production data, locating sites for wells, controlling the rate of extraction from wells, and maximizing the rate of production from individual wells and the reservoir as a whole. Some of these patents are described in the following paragraphs.
U.S. Pat. No. 5,992,519 to Ramakrishnan et al teaches a method and hardware for monitoring and controlling a plurality of production oil wells to satisfy predetermined, updatable production criteria. An oil reservoir model is used in conjunction with a reservoir simulation tool in order to determine a production strategy by which oil is controllably produced from the reservoir using flow valves. Information gleaned as a result of adjustments to the flow valves is used to update the reservoir model. Oil wells are drilled based on a fixed production strategy and the fluid flow rates from the wells, as adjusted, are based on a variable production strategy.
U.S. Pat. No. 5,706,896 to Tubel et al teaches a system for controlling and/or monitoring a plurality of production wells from a remote location. The control system is composed of multiple downhole electronically controlled electromechanical devices and multiple computer based surface systems operated from multiple locations. The system provides the ability to predict the future flow profile of multiple wells and to monitor and control the fluid or gas flow from either the formation into the wellbore, or from the wellbore to the surface. The control system is also capable of receiving and transmitting data from multiple remote locations such as inside the borehole, to or from other platforms, or from a location away from any well site.
U.S. Pat. No. 5,732,776 to Tubel et al teaches another similar system for controlling and/or monitoring a plurality of production wells from a remote location. The multi-zone and/or multi-well control system is composed of multiple downhole electronically controlled electromechanical devices and multiple computer based surface systems operated from multiple locations. This system has the ability to predict the future flow profile of multiple wells and to monitor and control the fluid or gas flow from either the formation into the wellbore, or from the wellbore to the surface. This control system is also capable of receiving and transmitting data from multiple remote locations such as inside the borehole, to or from other platforms, or from a location away from any well site.
U.S. Pat. No. 5,975,204 to Tubel et al teaches and claims a downhole production well control system for automatically controlling downhole tools in response to sensed selected downhole parameters without an initial control signal from the surface or from some other external source.
U.S. Pat. No. 4,757,314 to Aubin et al describes an apparatus for controlling and monitoring a well head submerged in water. This system includes a plurality of sensors, a plurality of electromechanical valves and an electronic control system which communicates with the sensors and valves. The electronic control system is positioned in a water tight enclosure and the water tight enclosure is submerged underwater. The electronics located in the submerged enclosure control and operate the electromechanical valves based on input from the sensors. In particular, the electronics in the enclosure uses the decision making abilities of the microprocessor to monitor the cable integrity from the surface to the well head to automatically open or close the valves should a break in the line occur.
U.S. Pat. No. 4,633,954 to Dixon et al teaches a fully programmable microprocessor controller which monitors downhole parameters such as pressure and flow and controls the operation of gas injection to the well, outflow of fluids from the well or shutting in of the well to maximize output of the well. This particular system includes battery powered solid state circuitry comprising a keyboard, a programmable memory, a microprocessor, control circuitry and a liquid crystal display.
U.S. Pat. No. 5,132,904 to Lamp teaches a system similar to the '954 patent wherein the controller includes serial and parallel communication ports through which all communications to and from the controller pass. Hand held devices or portable computers capable or serial communication may access the controller. A telephone modem or telemetry link to a central host computer may also be used to permit several controllers to be accessed remotely.
U.S. Pat. No. 4,969,130 to Wason et al teaches a system for monitoring the fluid contents of a petroleum reservoir, wherein a reservoir model is employed to predict the fluid flow in the reservoir, includes a check on the reservoir model by comparison of synthetic seismograms with the observed seismic data. If the synthetic output predicted by the model agrees with the observed seismic data, then it is assumed that the reservoir is being properly modeled. If not then the reservoir model, in particular its reservoir description, is updated until it predicts the observed seismic response. The seismic survey may be periodically repeated during the productive life of the reservoir and the technique used to update the reservoir model so as to ensure that the revised reservoir description predicts the observed changes in the seismic data and hence reflects the current status of fluid saturations.
U.S. Pat. No. 5,586,082 to Anderson et al teaches a method for identifying subsurface fluid migration and drainage pathways in and among oil and gas reservoirs using 3-D and 4-D seismic imaging. This method uses both single seismic surveys (3-D) and multiple seismic surveys separated in time (4-D) of a region of interest to determine large scale migration pathways within sedimentary basins, and fine scale drainage structure and oil-water-gas regions within individual petroleum producing reservoirs.
U.S. Pat. No. 5,798,982 to He et al teaches a method for the mapping and quantification of available hydrocarbons within a reservoir and is useful for hydrocarbon prospecting and reservoir management.
While these patents individually teach various aspects associated with locating reservoirs, locating sites for wells, controlling the rate of extraction from wells, and attempting to maximize the rate of production from individual wells and a reservoir as a whole, none of the above cited prior art or any other patents or literature suggests or teaches integrating all these many functions into a more comprehensive method for maximizing the production of gas and/or oil from the entire reservoir.
Thus, there is a need for a new and more comprehensive method for managing an oil and/or gas reservoir for the purpose of maximizing the production of gas and/or oil from a reservoir.
In addition, in the prior art, a development plan would be produced for a first reservoir field, an operator would make a decision from a number of alternatives available to him in relation to the first reservoir field, and then the operator would implement a particular process in the first reservoir field. At this point, the operator would focus his attention to a second reservoir field or a second property while allowing the first reservoir field or first property to be operated by a field staff and a maintenance staff. The first reservoir field would not receive any particular attention for several years when things started to go wrong in that first reservoir field. The operator would then re-focus his attention to the first reservoir field and ask how the resultant activity or results obtained from the first reservoir field or property differed from the operator's original expectations with regard to that first reservoir field. In addition, the operator would initiate a study to find out what happened with regard to the first reservoir field. This process seemed to be a “hit and miss” type of interest reflecting only a sporadic interest in the first reservoir field property.
Accordingly, in the above referenced quest to obtain a new and more comprehensive method for managing an oil and/or gas reservoir, there is a further need to provide a more organized, efficient, and automated process for automatically updating on a periodic basis the original development plan for the first reservoir field property when the resultant activity or results obtained from the first property are initially received. As a result, a new development plan can be produced for the first property and the new development plan can be implemented in connection with that first property following the generation of the results or resultant activity from the first property.